Update PR template

Now in sync with CONTRIBUTING.md

.github/PULL_REQUEST_TEMPLATE

@@ -10,16 +10,7 @@ Checklist:
 5. Tests pass,
 6. Linked to relevant issues
 
-Please make sure that your commit message summary line and pull
-request title match our commit message conventions; Examples:
+When you are writing pull request title and describing changes, follow
+commit message format in the CONTRIBUTING.md in the codebase root.
 
-- add(messaging): import webhooks api
-- upd(crm): check for error when saving page
-- add(system): api calls for creating bot users
-- fix(system): tests are running in transaction
-- ws(all): fix whitespace, formatted json
-
-More natural language commits are permitted, so you could commit
-as `Added api calls for bot user creation to system`, but you
-are encouraged to stick to the above format.
--->
+-->